apache/pulsar · error · IllegalArgumentException

Function tenant cannot be null

Error message

Function tenant cannot be null

What it means

FunctionConfigUtils.doCommonChecks validates a function's FunctionConfig before it can be created or updated. The first mandatory field is the tenant, the top-level namespace grouping in Pulsar. If tenant is null or empty, validation fails immediately with this IllegalArgumentException so an incomplete function config never reaches the broker.

Source

Thrown at pulsar-functions/utils/src/main/java/org/apache/pulsar/functions/utils/FunctionConfigUtils.java:791

        if (functionConfig.getMaxMessageRetries() != null && functionConfig.getMaxMessageRetries() >= 0) {
            throw new IllegalArgumentException("Message retries not yet supported in Go function");
        }
    }

    private static void verifyNoTopicClash(Collection<String> inputTopics, String outputTopic)
            throws IllegalArgumentException {
        if (inputTopics.contains(outputTopic)) {
            throw new IllegalArgumentException(
                    String.format(
                            "Output topic %s is also being used as an input topic (topics must be one or the other)",
                            outputTopic));
        }
    }

    public static void doCommonChecks(FunctionConfig functionConfig) {
        if (isEmpty(functionConfig.getTenant())) {
            throw new IllegalArgumentException("Function tenant cannot be null");
        }
        if (isEmpty(functionConfig.getNamespace())) {
            throw new IllegalArgumentException("Function namespace cannot be null");
        }
        if (isEmpty(functionConfig.getName())) {
            throw new IllegalArgumentException("Function name cannot be null");
        }
        // go doesn't need className. Java className is done in doJavaChecks.
        if (functionConfig.getRuntime() == FunctionConfig.Runtime.PYTHON) {
            if (isEmpty(functionConfig.getClassName())) {
                throw new IllegalArgumentException("Function classname cannot be null");
            }
        }

        Collection<String> allInputTopics = collectAllInputTopics(functionConfig);
        if (allInputTopics.isEmpty()) {
            throw new IllegalArgumentException("No input topic(s) specified for the function");
        }

View on GitHub (pinned to 820761864e)

Solutions

1. Set the tenant on the FunctionConfig before submitting, e.g. functionConfig.setTenant("public") (or pass --tenant to the CLI).
2. If loading from YAML/JSON, add the missing 'tenant' key to the config file.
3. Verify the field is populated after deserialization; empty-string tenants also fail, so trim/require a non-empty value.
4. Use a tenant that exists in the cluster (commonly 'public') if you are unsure which one to use.

Example fix

// before
FunctionConfig config = new FunctionConfig();
config.setNamespace("default");
config.setName("my-fn");
// after
FunctionConfig config = new FunctionConfig();
config.setTenant("public");
config.setNamespace("default");
config.setName("my-fn");

if (config == null || config.getTenant() == null || config.getTenant().trim().isEmpty()) {
    throw new IllegalArgumentException("FunctionConfig.tenant must be set before submission");
}

static boolean hasTenant(FunctionConfig c) {
    return c != null && c.getTenant() != null && !c.getTenant().trim().isEmpty();
}

try {
    FunctionConfigUtils.validateNonJavaFunction(functionConfig, null);
} catch (IllegalArgumentException e) {
    log.error("Invalid function config: {}", e.getMessage());
    // surface a friendly message asking for --tenant
}

When it happens

Trigger: Calling createFunction/updateFunction (via FunctionConfigUtils' createFunction paths, the functions worker REST API, or pulsar-admin functions create) with a FunctionConfig whose getTenant() returns null or the empty string; doCommonChecks is invoked from validateNonJavaFunction and validateJavaFunction.

Common situations: Building a FunctionConfig programmatically and forgetting setTenant(); YAML/JSON function config files that omit the 'tenant' key; CLI invocations missing the --tenant flag; configs deserialized from templates where tenant was left as a placeholder.

Understand the failure class

Background: "X is required", "field cannot be empty", error-the-field-is-required: missing required-field validation errors, explained — this error's family across 39 libraries.

Related errors

• When Guarantees == ATMOST_ONCE, autoAck must be equal to tru
• Function namespace cannot be null
• Function name cannot be null
• there are redundant configure for listener `${listenerName}`
• must not specify `${hostPort}` to different listener.

AI-assisted analysis of apache/pulsar@820761864e (2026-09-06). Data as JSON: /api/errors/a83051718aabb06b. Report an issue: GitHub.